Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

1,153 results found
Article

Fibrous hamartoma of infancy

Fibrous hamartoma of infancy is a rare benign tumor of the subcutaneous tissues seen in children. More than 90% of cases present in the first year of life with up to 25% being congenital 1. Epidemiology There is a reported male:female ratio of 2:1 but the exact incidence is unknown 2. Clinica...
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Fibroxanthoma of bone

Fibroxanthoma of bone is a confusing term that is sometimes used to encompass non-ossifying fibroma and fibrous cortical defect, and at other times synonymously with just non-ossifying fibromas. As non-ossifying fibroma and fibrous cortical defect are histologically the same, and differ only in ...
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Fibular hemimelia

Fibular hemimelia is a congenital lower limb anomaly characterized by partial or complete absence of the fibula and includes a spectrum ranging from mild fibular hypoplasia to complete fibular aplasia 1. Epidemiology Although rare in occurrence, it is the most common congenital absence of long...
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Filar cyst

A filar cyst is an incidental finding on neonatal lumbar sonography located in the filum terminale of the spinal cord. It is considered a normal variant and is often confused for a ventriculus terminalis, a smooth dilated cavity of the central canal, located within the conus medullaris. The inc...
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Five Ts of cyanotic congenital heart disease (mnemonic)

A mnemonic to remember the most important congenital heart defects associated with cyanosis is: five Ts Mnemonic T: tetralogy of Fallot (TOF) T: transposition of the great arteries (TGA) T: truncus arteriosus T: total anomalous pulmonary venous return (TAPVR) T: tricuspid valve abnormalit...
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Flat floor of fourth ventricle sign

The flat floor of fourth ventricle sign is useful in detecting a pontine mass and is a sign of mass effect. The normal floor of the fourth ventricle (remember that the floor is anterior) normally slopes upwards towards the midline, with the facial colliculi visible on either side.  It is a non-...
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Focal periphyseal edema zone

Focal periphyseal edema zones, also known as FOPE zones, are regions of bone marrow edema seen on MRI that are principally located at the physes about the knee. They are thought to represent potentially painful manifestations of physiologic physeal fusion 1. Epidemiology FOPE zones are seen in...
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Foot (weightbearing lateral)

The weightbearing lateral foot radiograph is important in the assessment of foot alignment and the diagnosis of abnormalities that cause malalignment and foot pain. Nonweightbearing views (e.g. oblique foot radiograph) are inadequate for the assessment of alignment because the bones of the feet ...
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Foramen ovale (cardiac)

The foramen ovale (or ovalis) is the opening in the interatrial septum in the fetal heart that allows blood to bypass the right ventricle and non-ventilated lungs, shunted from the right atrium to the left atrium. Specifically it represents the opening between the upper and lower portions of the...
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Forearm fracture

Forearm fractures are a group of fractures that occur in the forearm following trauma. The radius and ulna are bound together at the proximal and distal radioulnar joints and act as a ring. Like elsewhere in the body, it is difficult to only fracture one bone if there is a bony ring. If the radi...
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Foreign body ingestion series (pediatric)

The suspected foreign body ingestion series is a set of radiographs utilized to detect and identify foreign bodies in the gastrointestinal tract. It involves an AP and lateral radiograph of the neck, chest, and abdomen ensuring adequate coverage of the entire gastrointestinal tract 1. Patient p...
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Foreign body inhalation series (pediatric)

The suspected foreign body inhalation series although not a primary port of investigation aims to detect and identify both foreign bodies or the secondary signs of inhaled foreign bodies 1. It involves a frontal chest radiograph in both the inspiration and expiratory phases and, in some cases, b...
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Fossa ovale

The fossa ovale (or ovalis) is the small oval depression in the interatrial septum at the site of the closed foramen ovale, which closes once fetal circulation ceases in the first few minutes of postnatal life. It represents the overlapping primary and secondary septa of the interatrial septum. ...
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Fountain sign (acute idiopathic scrotal edema)

The fountain sign is sonographic sign described in acute idiopathic scrotal edema (AISE). It refers to the appearance of the pattern of vascularity seen during transverse color Doppler sonography of the scrotum with both testes together 1. In these transverse views in patients with AISE, marked...
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Fourth ventriculocoele

A fourth ventriculocoele is large posterior fossa cyst which remodels, thins and eventually erodes through the occipital bone to form an occipital encephalocoele. It may be classified as part of the Dandy-Walker continuum, but this is controversial.
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Fowler syndrome

Fowler syndrome, also known as proliferative vasculopathy and hydranencephaly-hydrocephaly syndrome (PVHH), is a rare inherited condition. Terminology Not to be confused with Fowler syndrome of urinary retention, a condition caused by primary failure of urethral sphincter relaxation resulting ...
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F P Weber syndrome

F P Weber syndrome (FPWS) is a traditional eponymous denomination of a certain type of angiodysplasia, that would nowadays rather be called a mixed hemolymphatic congenital vascular malformation (CVM) with arteriovenous (AV) shunting, based on the Hamburg classification of CVMs. In his original...
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Fracture translation

Fracture translation (also called translocation) describes the movement of fractured bones away from each other. In some cases, people will just use the term displacement to describe translation. However, displacement should really be used as a broad term that refers to angulation, translation a...
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Fragile X syndrome

Fragile X syndrome is the most common inherited cause of cognitive disability and is the result of the mutation in the fragile X mental retardation 1 (FMR1) gene.  Epidemiology Although the degree of cognitive disability is typically more severe in males with fragile X syndrome, females can al...
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Fraser syndrome

Fraser syndrome is an extremely rare congenital syndromic anomaly.  Epidemiology The estimated incidence is at around 0.04:10,000 live-born infants and 1:10,000 stillbirths. Clinical spectrum The syndromic spectrum can comprise of: cryptophthalmos syndactyly: often cutaneous tracheal atre...
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Freiberg disease

Freiberg disease, also known as Freiberg infraction, is osteochondrosis of metatarsal heads. It typically affects the 2nd metatarsal head, although the 3rd and  4th may also be affected. It can be bilateral in up to 10% of cases. Epidemiology It is most common in females aged 10-18 years (male...
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Frontal bossing

Frontal bossing is a calvarial radiographic feature where the front of the skull appears protruding anteriorly. It is best appreciated on a sagittal or lateral image. Pathology This feature can be seen in many conditions (in alphabetical order): 18q syndrome acromegaly achondroplasia ß-tha...
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Frontonasal dysplasia

Frontonasal dysplasia, also known as median cleft face syndrome, is a rare disorder characterized by midline defects involving the face, head, and central nervous system. Epidemiology Frontonasal dysplasia is considered to be a very rare condition, with approximately 100 cases having been repo...
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Frykman classification of distal radial fractures

The Frykman classification of distal radial fractures is based on the AP appearance and encompasses the eponymous entities of Colles fracture, Smith fracture, Barton fracture, chauffeur fracture. It assesses the pattern of fractures, involvement of the radioulnar joint and presence of a distal u...
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Fucosidosis

Fucosidosis is a rare inherited autosomal recessive lysosomal storage disorder, hypomyelinating disorder, and mucopolysaccharidosis-like disorder, characterized by multiorgan accumulation of fucose-containing products. Epidemiology It is considered very rare, with approximately only 100 cases ...
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Fukuyama congenital muscular dystrophy

Fukuyama congenital muscular dystrophy (FCMD) is a form of congenital muscular dystrophy. Epidemiology FCMD is almost exclusively found in Japan where it has an incidence of 2-4 per 100,000 infants and is the second most common muscular dystrophy after Duchenne muscular dystrophy 1,2. However,...
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Gage sign

The Gage sign is a V-shaped lucent defect at the lateral portion of the epiphysis and/or adjacent metaphysis. It is pathognomonic for Legg-Calve-Perthes disease. It may occur early in the disease and is one of the five indicators of a worse prognosis, which are: Gage sign  calcification later...
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Galeazzi fracture-dislocation

Galeazzi fracture-dislocations consist of fracture of the distal part of the radius with dislocation of distal radioulnar joint and an intact ulna. A Galeazzi-equivalent fracture is a distal radial fracture with a distal ulnar physeal fracture 2. Epidemiology Galeazzi fractures are primarily e...
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Gallbladder ghost triad

Gallbladder ghost triad is a term used on ultrasound studies when there is a combination of three gallbladder features on biliary atresia: atretic gallbladder, length less than 19 mm irregular or lobular contour  lack of smooth/complete echogenic mucosal lining with an indistinct wall The te...
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Galloway-Mowat syndrome

Galloway-Mowat syndrome (GAMOS) is a rare autosomal recessive disorder characterized by nephrotic syndrome and central nervous system (CNS) abnormalities, namely microcephaly. Epidemiology Galloway-Mowat syndrome is considered extremely rare. Approximately 40 cases have been reported worldwide...
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Ganglioglioma

Gangliogliomas are uncommon, usually low-grade, CNS tumors. Epilepsy is a common clinical presentation and this tumor has a typical occurrence in the temporal lobes, although they have been described in all parts of the central nervous system. Their appearance on imaging is very variable: from ...
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Ganglioneuroma

Ganglioneuromas are fully differentiated neuronal tumors that do not contain immature elements and potentially occur anywhere along the peripheral autonomic ganglion sites.  On imaging, usually, they present as well-defined solid masses and can be quite large at presentation. Generally, they ar...
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Gastric duplication cyst

Gastric duplication cysts are rare congenital foregut duplication cysts affecting the stomach. Gastrointestinal tract duplication cysts (GTDCs) most commonly affect the ileum, followed by the esophagus, large bowel, and jejunum; gastric location accounts for less than 10% of all gastrointestinal...
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Gastric volvulus

Gastric volvulus is a specific type of volvulus that occurs when the stomach twists on its mesentery. It should be at least 180° and cause bowel obstruction to be called gastric volvulus. Merely gastric rotation on its root is not considered gastric volvulus. Epidemiology Organo-axial volvulus...
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Gastro-esophageal reflux disease

Gastro-esophageal reflux disease (GERD) is a spectrum of disease that occurs when gastric acid refluxes from the stomach into the lower end of the esophagus across the lower esophageal sphincter (LES). Clinical presentation Common clinical features in adults include epigastric and retrosternal...
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Gastroschisis

Gastroschisis refers to extra-abdominal herniation (evisceration) of fetal or neonatal bowel loops (and occasionally portions of the stomach and or liver) into the amniotic cavity through a para-umbilical anterior abdominal wall defect.   Epidemiology The estimated incidence is at around 1-6 p...
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Gaucher disease

Gaucher disease (GD) is the most common lysosomal storage disorder in humans. It is an autosomal recessive, multisystem disease arising from a deficiency of glucocerebrosidase or beta-glucosidase activity, resulting in the accumulation of a glycolipid (glucocerebroside) within the lysosomes of m...
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Generalized increased bone density in children

The causes of generalized increased bone density in pediatric patients can be divided according to a broad category of causes: skeletal dysplasias osteopetrosis pyknodysostosis metabolic renal osteodystrophy poisoning lead dense metaphyseal bands cortex and flat bones may also be slight...
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Gerbode defect

The Gerbode defect describes a rare abnormal left-to-right shunt between the left ventricle and right atrium through a defect in the atrioventricular septum, usually congenital in etiology. Epidemiology Gerbode defects are rare congenital cardiac anomalies, and are thought to account for less ...
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Germinal matrix hemorrhage

Germinal matrix hemorrhages, also known as periventricular-intraventricular hemorrhages (PVIH), are the commonest type of intracranial hemorrhage in neonates and are related to perinatal stress affecting the highly vascularized subependymal germinal matrix. The majority of cases occur in prematu...
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Germinal matrix hemorrhage (grading)

Grading of germinal matrix hemorrhage has taken several forms over the years. The most commonly used system is the sonographic grading system proposed by Burstein, Papile et al.  Classification grade I restricted to subependymal region/germinal matrix which is seen in the caudothalamic groove...
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Ghost vertebra

Ghost vertebra is a sign, that is generally used synonymously with bone-within-a-bone vertebra, and as such, the causes form a subset of those causing bone within a bone appearance 2: Thorotrast administration: bone within a bone appearance due to temporary growth arrest 1 stress line rickets...
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Gillespie syndrome

Gillespie syndrome is a rare genetic condition presenting as a mydriasis, secondary to an omnipresent partial aniridia. The abnormal iris is bilateral, with a highly-specific scalloped inner margin, due to hypoplasia of the central constrictor pupillae fibers. Associated features include an unch...
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Global testicular infarction

Global testicular infarction is fortunately rare, and is most commonly seen in the context of testicular torsion. However rarely it can occur secondary to other causes.  Pathology Etiology testicular torsion epididymo-orchitis 1-4 iatrogenic surgery, e.g. inguinal hernia repair 7 post-EVA...
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Glutaric aciduria type 1

Glutaric aciduria type 1 is a leukodystrophy that can be subclassified as an organic acidopathy. It has a highly variable clinical presentation, and laboratory investigations are not always diagnostic. Imaging, therefore, has an important role to play as the MRI features can be characteristic. ...
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Glycogen storage disease

Glycogen storage disease (GSD) refers to a number of syndromes which are characterized by a defect in synthesis, metabolism or storage of glycogen. Pathology There are many types of GSD: type I: von Gierke disease type II: Pompe disease type III: Cori or Forbes disease type IV: Andersen di...
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Glycogen storage disease type I

Glycogen storage disease type I (GSD-I), also known as von Gierke disease, is a type of glycogen storage disease where there is excess deposition of glycogen primarily in the liver, but also in the kidney and small bowel. Epidemiology It occurs approximately one in every 100,000 live births 2,...
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Glycogen storage disease type II

Glycogen storage disease type II, also known as Pompe disease or acid maltase deficiency disease, is an inherited lysosomal disorder characterized by abnormal glycogen accumulation within lysosomes. It is a multisystem disorder involving the heart, skeletal muscle and liver. It is caused by a de...
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Goldenhar syndrome

Goldenhar syndrome, also known as oculo-auriculo-vertebral spectrum (OAVS), Goldenhar-Gorlin syndrome or facio-auriculo-vertebral dysplasia, is a complex congenital anomaly characterized by abnormalities of the ears, eyes and vertebrae. Epidemiology The estimated incidence is at 1 in 3000-5000...
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Gomez-Lopez-Hernandez syndrome

Gomez-Lopez-Hernandez syndrome, also known as cerebellotrigeminal-dermal dysplasia, is a rare phakomatosis characterized by rhombencephalosynapsis, parietal-occipital scalp alopecia, brachycephaly, facial malformations and trigeminal anesthesia.  History and etymology It is named after Manuel ...
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Gonadal dysgenesis

Gonadal dysgenesis refers to a spectrum of anomalies with abnormal development of the gonads. It falls under the even broader group of disorders of gender development. Pathology In many cases the gonads are replaced by fibrous tissue. Subtypes complete gonadal dysgenesis (CGD) / Swyer syndro...
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Gonadoblastoma

Gonadoblastomas are uncommon sex cord / stromal tumors. They are associated with disorders of sexual development (previously known as "intersex disorders"). Epidemiology The vast majority are found <30 years of age. Most are discovered in the perinatal period. May occur in phenotypic males or ...
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Gracile bones (mnemonic)

The causes of gracile bones can be recalled with the following mnemonic: NIMROD Mnemonic NIMROD N: neurofibromatosis I: immobilization/paralysis M: muscular dystrophy, e.g. Duchenne muscular dystrophy R: rheumatoid arthritis (juvenile RA) O: osteogenesis imperfecta D: dysplasia, e.g. Ma...
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Graf method for ultrasound classification of developmental dysplasia of the hip

The Graf method for ultrasound classification system for developmental dysplasia of the hip (DDH) in infants, combines both alpha and beta angles. There are a number of additional subdivisions, which are often not used clinically.  As a general rule, the alpha angle determines the type and in s...
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Greenstick fracture

Greenstick fractures are incomplete fractures of long bones and are usually seen in young children, more commonly less than 10 years of age. They are commonly mid-diaphyseal, affecting the forearm and lower leg. They are distinct from torus fractures. Pathology Mechanism Greenstick fractures ...
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Greig cephalopolysyndactyly syndrome

The Greig cephalopolysyndactyly syndrome (GCPS) is a rare pleiotropic, multiple congenital anomaly syndrome. It is primarily characterized by: polydactyly-polysyndactyly: preaxial polydactyly (most common 2) or mixed pre- and postaxial polydactyly true ocular hypertelorism macrocephaly fro...
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Grey matter heterotopia

The grey matter heterotopias are a relatively common group of conditions characterized by interruption of normal neuronal migration from near the ventricle to the cortex, thus resulting in "normal neurons in abnormal locations" 2. They are a subset of disorders of cortical formation 3-4. Grey m...
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Growth arrest lines

Growth arrest lines, also known as growth resumption lines, Harris lines or Park lines, are alternating transverse rings of sclerosis at the metaphysis of a long bone. Pathology The radiographic finding occurs from alternating cycles of osseous growth arrest and growth resumption. This appears...
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Gymnast wrist

Gymnast wrist is a term that used to describe variety of chronic overuse injuries of the wrist in gymnasts with immature skeleton. Gymnast wrist is combined of osseous and ligamentous injury and usually manifests as a chronic Salter-Harris type I fracture of the distal radial physis on radiograp...
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Hematuria (pediatric)

Hematuria in a child is evaluated differently than in an adult in two main respects: there is a lower likelihood of a malignancy (renal or bladder) causing the hematuria preference is given to nonionizing radiation Pathology Hematuria can be considered in three main forms: "gross" hematuria...
Article

Hemoglobinopathies

A hemoglobinopathy is a genetic disorder which alters the structure of hemoglobin 1. The result is reduced oxygen-carrying capacity of the blood to the tissues, and other sequelae. Clinical presentation Clinical presentation varies, is related to hypoxia, and characteristically includes the fo...
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Hemolytic uremic syndrome

Hemolytic uremic syndrome (HUS) is a multisystem thrombotic microangiopathic disease characterized by the triad of renal failure, hemolytic anemia and thrombocytopenia. It is the most common cause of renal failure in infancy and childhood requiring dialysis.  There are two forms of this syndrom...
Article

Hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH), also known as macrophage activation syndrome when occurring in the setting of a rheumatologic disorder, is a non-malignant but often-fatal disorder of immune dysregulation affecting multiple organs. Epidemiology It typically affects infants and young c...
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Halberd pelvis

A halberd pelvis refers to a pathognomonic appearance of the pelvis seen in metatropic dysplasia, a rare form of spondyloepimetaphyseal dysplasia. hypoplastic ilia with narrow sacrosciatic notches horizontal acetabular roofs with small associated notches superior to their lateral borders prom...
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Hand-foot-and-mouth disease

Hand-foot-and-mouth disease is a viral illness that manifests as vesicular eruptions on the hands and feet as well as painful ulcers of the oral mucosa. Symptoms usually resolve spontaneously in 7-10 days. In most cases, there is a prodrome of fever, vomiting, diarrhea, anorexia, and malaise. ...
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Hand-foot syndrome (chemotherapy)

Hand-foot syndrome, also known as palmar-plantar erythrodysaesthesia or Burgdorf reaction, is a benign, aseptic, self-limiting complication of many chemotherapeutic agents characterized by a widespread erythema, edema and ulceration of the hands and feet.  Causative drugs Many chemotherapeutic...
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Hand-foot syndrome (sickle cell disease)

Hand-foot syndrome, also simply referred to as dactylitis, is a self-limiting manifestation of a vaso-occlusive crisis in individuals with sickle cell anemia. Terminology Dactylitis is not a specific finding in sickle cell disease, therefore cautious usage is advised if one chooses to employ i...
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Hand series (pediatric)

The hand series for pediatrics often consist of a posteroanterior and lateral view only in order to minimize radiation dose to the patient. This may vary depending on the department.  Indications trauma with suspected fracture suspected dislocation foreign body detection Projections Standa...
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Harlequin eye deformity

The harlequin eye deformity is characterized by elevation of the superolateral corner of the orbit. It may be seen in unilateral (plagiocephaly) or bilateral (brachycephaly) coronal suture synostosis. History and etymology The term harlequin eye derives from the appearance of the eyes on a har...
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Harrison sulcus

The Harrison sulcus or Harrison groove refers to a groove at the lower end of the rib cage seen in young children/infants with abnormally weak bones (e.g. rickets) or chronic respiratory disease (e.g. severe asthma). The lower chest is drawn in with flaring of the rib margin. The exact cause is ...
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Haystack sign (pneumomediastinum)

The haystack sign on chest radiographs in pediatric patients is indicative of pneumomediastinum. The pediatric heart is surrounded above and below with gas, giving it an appearance of a haystack from Monet's paintings. 
Article

Head ultrasound

Head ultrasound (HUS), also called cranial ultrasound (CUS), is obtained for the diagnosis and follow-up of premature and sick neonates. Advantages Head ultrasound has the advantages of: accessibility mobility, i.e. bedside scanning at the NICU and neonatal ward requiring no sedation enabl...
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Heavy charged particle therapy

Heavy charged particle therapy (also known as heavy ion radiotherapy) is a type of particle therapy that uses ionized atoms (e.g. neon, argon, silicon, carbon etc.). Currently carbon ions are most commonly employed, termed carbon ion radiotherapy (CIRT). It is a technically-demanding technique ...
Article

Heiner syndrome

The Heiner syndrome is a rare form of primary pulmonary hemosiderosis associated with an allergy to cow's milk. The syndrome includes: rectal blood loss with hypochromic microcytic anemia pulmonary infiltrates (often recurrent) hypoproteinemia See also pulmonary hemosiderosis
Article

Hemiconvulsion-hemiplegia epilepsy syndrome

Hemiconvulsion-hemiplegia epilepsy syndrome (HHE) is a clinical syndrome of infancy or early childhood that is associated with seizures, cerebral hemiatrophy and transient or permanent epilepsy. It refers to the characteristic holohemispheric global atrophy of one hemisphere, that is independen...
Article

Hemihyperplasia

Hemihyperplasia, also known as hemihypertrophy, is asymmetry in size between the right and left of the body, more than can be attributed to normal variation. Terminology Hemihyperplasia is more scientifically correct than hemihypertrophy as the cells are hyperplastic rather than hypertrophied ...
Article

Hemimegalencephaly

Hemimegalencephaly is a rare congenital disorder of cortical formation with hamartomatous overgrowth of all or part of a cerebral hemisphere. This results from either increased proliferation or decreased apoptosis (or both) of developing neurons 2. Epidemiology Hemimegalencephaly is a cryptoge...
Article

Hemimelia

Hemimelia is the term used to describe a partial or complete congenital absence of the distal half of a limb. It comprises of: fibular hemimelia tibial hemimelia ulna hemimelia radial hemimelia
Article

Hepatic mesenchymal hamartoma

Hepatic mesenchymal hamartoma are uncommon benign hepatic lesions which are mostly seen in children under the age of 2. Some authors consider them to be developmental anomalies rather than cystic neoplasia 9,12.  Epidemiology age typically occurs in children and neonates 3 most cases present...
Article

Hepatoblastoma

Hepatoblastoma is the most common primary malignant liver tumor in children under four years of age who usually present with painless abdominal mass and raised AFP. It is tumor of embryonic origin. Epidemiology Most cases are seen during the first 18 months of life and diagnosis in adulthood i...
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Hepatoblastoma histological classification

Although hepatoblastomas can be histologically classified into a variety of subtypes, it is important to remember that with the possible exception of small cell undifferentiated subtype, prognosis is independent of histology when adjusted for stage gender and age 1. major categories epithelial...
Article

Hepatoblastoma (staging)

As expected there are a number of different staging systems for hepatoblastoma. Staging PRETEXT grouping system of pediatric liver tumors not specific to hepatoblastoma; used in all pediatric liver tumors Intergroup staging system specific for hepatoblastoma (see below) Intergroup staging ...
Article

Hepatosplenomegaly

Hepatosplenomegaly is simply the simultaneous presence of a pathologically-enlarged liver (hepatomegaly) and spleen (splenomegaly). Pathology Etiology Infection Many, many infections can produce a mild concurrent enlargement of the liver and spleen. This list is by no means exhaustive! vira...
Article

Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps syndrome

Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC) syndrome is an autosomal dominant monogenic COL4A1-related disorder. Epidemiology The exact prevalence is unknown. Clinical presentation The cardinal features of HANAC syndrome are helpfully described in the name of...
Article

Hereditary connective tissue disease

Hereditary connective tissue diseases are a group of connective tissue disease that have a degree of inheritance risk. They include:  Marfan syndrome: genetic disease causing abnormal fibrillin Ehlers-Danlos syndrome: progressive deterioration of collagen and affects joints, heart valves, orga...
Article

Hereditary hyperphosphatasia

Hereditary hyperphosphatasia, also known as juvenile Paget disease, is an autosomal recessive osteopathy due to osteoprotegerin deficiency which has a similar clinicoradiological presentation to adult Paget disease of bone. Terminology The term "hyperphosphatasia" has been used to describe a h...
Article

Hereditary multiple exostoses

Hereditary multiple exostoses, also known as diaphyseal aclasis or osteochondromatosis is an autosomal dominant condition, characterized by the development of multiple osteochondromas. Epidemiology Hereditary multiple exostoses demonstrate an autosomal dominant inheritance pattern, with incomp...
Article

Hereditary spherocytosis

Hereditary spherocytosis (HS) (also known as Minkowski-Chauffard disease 1) is a group of hemolytic anemias due to a genetic abnormality of the erythrocyte cell membrane resulting in spherocytes. The clinical spectrum is broad, from a subclinical state to severe transfusion-dependent anemia. Ep...
Article

Hernia (general)

Hernias (or herniae) are a common pathological entity, in which an anatomical structure passes into an abnormal location via an opening. The opening may be a normal physiological aperture (e.g. hiatus hernia: stomach passes through the diaphragmatic esophageal hiatus) or pathological. Iatrogeni...
Article

Herpes simplex encephalitis

Herpes simplex (HSV) encephalitis is the most common cause of fatal sporadic fulminant necrotizing viral encephalitis and has characteristic imaging findings.  Two subtypes are recognized which differ in demographics, virus, and pattern of involvement. They are 1: neonatal herpes encephalitis ...
Article

Heterotaxy syndrome

Heterotaxy syndrome or situs ambiguus (also commonly, but etymologically less correctly, spelled situs ambiguous) is a disturbance in the usual left-right distribution of the thoracic and abdominal organs that does not entirely correspond to the complete mirror image (situs inversus). It occurs...
Article

Hiccups

Hiccups (or hiccoughs), medical term singultus (rarely used), are an unpleasant phenomenon, experienced by everyone on occasion, and usually self-limiting. However the much rarer intractable chronic form can be extremely debilitating. Epidemiology Hiccups are a symptom that has probably been e...
Article

Hilgenreiner line

The Hilgenreiner line is a line drawn horizontally through the inferior aspect of both triradiate cartilages. It should be horizontal but is mainly used as a reference for the Perkin line and measurement of the acetabular angle. This line with the other lines and angles are used in the diagnosi...

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